You might recall a change to the way the notification long-press worked in Android 5.0. Prior to that, you could jump straight into App Info with a long-press, but Lollipop changed it to a notification settings link. Now in the M preview there's a way to access the App Info again, but it takes another tap.

When you long-press a notification in the M preview, there's still that "i" button that takes you to the notification settings for the app. However, now there's another "i" at the top of the notification settings. Tap this one and you get to the App Info screen.

Is it a little roundabout? Yeah, but it's more convenient than the overview icon shortcut, which only works when developer options are enabled.